1. Field of the Invention
The present invention relates to an onboard power supply apparatus in which a plurality of power storage modules each including a plurality of power storage devices are connected to one another.
2. Description of Related Art
International Publication No. WO2014/083600 discloses a battery module in which a plurality of cylindrical batteries are arranged with one longitudinal ends of the cylindrical batteries embedded in a holder.
An onboard power supply apparatus may be configured by connecting a plurality of battery modules described in WO2014/083600, for example, and it is possible to promote effective use of the space in a vehicle if the plurality of battery modules are stacked in the vertical direction. A positive electrode terminal (or negative electrode terminal) of an upper battery module is electrically connected to a negative electrode terminal (or positive electrode terminal) of the lower battery module in series using a bus bar, and in this case, the bus bar is provided in the vertical direction.
Meanwhile, if the battery modules are vertically stacked, and are mounted on a vehicle in this state, vertically stacked battery modules can be fixed to the vehicle with brackets. For example, a pair of brackets are disposed in a manner as to hold the battery modules therebetween from both longitudinal sides of the battery modules. One end of each bracket is fixed to a floor panel or a frame of the vehicle, and the other end thereof is fixed to the longitudinal end of each of the vertically stacked battery modules.
At this time, if the bus bar is vertically disposed at the longitudinal ends of the battery modules, a fixing structure of the vertically stacked battery modules using the bracket (a contact point between the longitudinal ends of the battery modules and the bracket), and a connecting structure between upper and lower battery modules using the bus bar (an electrical connecting path between the battery modules) interfere with each other.
It may be considered to connect the upper and lower battery modules in a manner as to bypass the contact point between the longitudinal ends of the battery modules and the bracket. In this case, the bus bar extending from an electrode terminal of the upper battery module is once led outward of the bracket. The bus bar so located outward of the bracket as to avoid the contact point between the ends and the bracket is then downwardly extended inward of the bracket again so as to be connected to the electrode terminal of the lower battery module. However, in this case, it is required to provide a hole through which the bus bar is inserted between the outer side and the inner side of the bracket. The through-hole formed in the bracket deteriorates strength of the bracket, and thus it is required to reinforce the bracket to improve its strength, and a part of the bus bar is located outward of the bracket, and thus an energizing region of the battery modules is exposed to the outside.